Fire crews have prepared all they can for the stronger winds forecast in Tasman this afternoon where a massive blaze has burned since Tuesday.

At a media stand up this morning, fire crews revealed that they have 100 per cent of the perimeter contained, but that is not entirely secure.

Fire and Emergency New Zealand incident controller John Sutton said the fire was active last night but the weather conditions for control efforts were favourable with light winds.

"It's moving very, very slowly," he said at a press conference this morning.

"We now predict with the current fire it will take six hours for that fire to burn to the river flats from where it is."

Sutton said the fire was less than 10km away from Wakefield. He described the river flat area was a double-edged sword, if the fire moved there it was the best opportunity to put it out but if it had strong wind behind it they would not be able to put firefighters in front of the moving blaze.

"It's not contained."

"I am worried about tomorrow, to be honest," he said.

Reporter Chelsea Daniels told Francesca Rudkin that they are working to create a "buffer zone" between the fire zone and the perimeter of around 30 metres.

However, if the wind picks up, that could put the effort at risk.

"Winds are expected to reach 45 kilometres this afternoon. They are pretty confident they can manage 50 kilometres an hour. Once it gets past there, they will have to start bringing down the helicopters and bringing out the men."

Outdoor activities that can generate sparks or fire are also prohibited, and include gas cutting, welding, angle grinding, and all use of chainsaws and scrub/bar cutters.

Commercial forest harvesting activities are also to cease, but provision can be made for the loading and mobilising of harvested material from landings.

Smith said he was mindful this would cause some inconvenience, but it was an essential precaution to help prevent more fires during the current period of extreme fire danger.

"We are not expecting this directive to limit activities where there is adequate [pressurised] fire control available, or those activities not generating fire risk such as horticultural spraying or feeding stock," he said.

"Landowners should be aware that many activities on land can cause fires and people should take action and be aware of what constitutes good fire management protocol.

The announcement comes after an estimated 170 houses were asked to prepare to evacuate in the Wai-iti area, just south of Wakefield, last night.

They join a mass movement that has already displaced about 2500 to 3000 people - as the fire has taken control of 2100ha, with a 27km perimeter.

Daniels says that there has been some frustration from residents on how they were being briefed, which Civil Defence has taken on board.

She spoke with one man who described his evacuation as feeling more like an arrest.

Kempthrone says that he and Civil Defence are aware of how challenging the evacuation is for people, but the primary goal is to keep people and property safe.

As of 11.30pm yesterday there were still active hotspots continue to hamper efforts for re-entry in Eves Valley, and an active fire area in Pigeon Valley. Teapot Valley was said to be a matter of priority for this morning.

"The priority for this operation remains protection of life and public safety," Civil Defence said.

Anyone preparing to evacuate was asked to find any house pets and bring them inside, leave cellphones on and charged, prepare essential items such as food, clothing and medication, and ensure their vehicle had enough fuel for the return trip.

Meanwhile, two men have been arrested on separate arson charges unrelated to the fire.

Both men, aged 27 and 24, have been charged over rubbish skip fires that are unrelated to each other.